Over the past several decades much investigation has taken place in an attempt to understand the mechanisms of friction particularly as arising with respect to two contacting sliding surfaces. The causes of friction between sliding surfaces is generally discussed, for example, in the article "The Genesis of Friction" by N. P. Suh and H. C. Sin, WEAR, 69(1981) Elsevier Sequoia S.A., Lausanne, Switzerland, pages 91-114. In such paper the authors pointed out that friction coefficient is not an inherent material property but is composed of three principal components, one due to the deforming asperities (roughness) of the surface, another due to plowing of the surface by wear particles, and another due to adhesion.
Further study has shown that the significance of wear effects can be severe for many materials, such as plastic materials, wherein the interfacial wear debris which is generated when two surfaces are in slidable contact is shown to have very important adverse effects on the friction coefficient as well as on other related wear behavior.
Particularly in polymer-based materials, plastic or visco-elastic deformation of the interfacial wear debris can contribute significantly to the total friction coefficient and the presence thereof can cause instabilities in the time-dependent friction behavior of the material. Since it is desirable to maintain a substantially constant coefficient of friction over time it would be helpful to reduce or eliminate the effects of interfacial wear debris at the sliding interface.